A rich communication suite (RCS: Rich Communication Suite) solution is an integrated communication and information sharing platform that crosses communication networks and Internet. A user may use a real mobile phone number as a login account to perform instant messaging (IM: Instant Messaging) communication with a contact through a personal computer (PC: Personal Computer) client, a web (Web) client or a mobile phone client of the RCS solution, or upload, download and share content such as pictures, music, videos and texts. Not only can the RCS solution expand a social network of the user, but also can provide a diverse life style for the user.
However, like an ordinary IM interaction tool, if two users need to perform interaction (such as IM interaction and file interaction) by using the same type of clients, the RCS solution requires that the two users should be registered users of a system corresponding to the clients. For example, if user A and user B need to perform interaction through RCS clients, both user A and user B should be registered users of an RCS system. As a result, registered users of a system (IM system, RCS system, and so on) cannot interact with unregistered users of the system.